Steam boiler



March 19, 1940. G. A. REHM STEAM BOILER Filed'July 28, 1938 60:24 VAREHM O I. QM .o o o I 2 o M o u 2 T 0 V 2 Patented Mar. 19, 1940 UNITEDSTATES PATENT orrics STEAM BOILER Application July 28, 1938, Serial No.221,664

5 Claims.

This invention relates to steam boilers, and more particularly toboilers of the water tube typ One common form of water tube boilercomprises a transverse lower water drum from which a bank of steamgenerating tubes extends upwardly across the path of flow of the furnacegases, and in many instances water wall tubes have been connected attheir upper ends to this drum. These water, wall tubes discharge largequantities of steam into the drum, and in some cases the rapidcirculation of water through the drum has carried much of this steaminto the steam generating tubes to mingle with the steam which isproduced therein, causing such a congestion in these tubes as to blockthe circulation through them. Consequently the tubes have becomeoverheated and damaged so seriously as to require replacement. Thesefacts have been recognized and it has been proposed heretofore toinstallconnecting tubes inside the drum between the upper ends of thewater wall tubes and the lower ends of certain of the steam generatingtubes which are swept by gases of comparatively low temperature. Theseconnecting tubes are difiicult to install or remove, they form a seriousrestriction to the circulation of water through the drum, and theyprevent access to the ends of the steam generating tubes and water walltubes. I

It is accordingly one object of the'invention to provide an improvedmeans for conducting steam from water wall tubes through the lower drumof a boiler without unduly restricting the circulation of water throughthe drum.

I It is a further object of the invention to provide an improved steamconducting means which can be readily installed in the lower drum of aboiler and easily removed therefrom, and which will not prevent accessto the tubes connected to the drum.

With these and other objects in view, as will be apparent to thoseskilled in the art, the invention resides in the combination of partssets forth in the specification and covered by the claims ap-,

The embodiment illustrated comprises a transverse upper steam-and-waterdrum Ill and a transverse lower water drum H located beneath the drum Iand connected thereto by a bank of upright, water tubes l2. A bank ofwater tubes M extends upwardly and forwardly from the front portion ofthe drum H to an upper water drum [5 which is connected to thesteamand-water drum H) by a bank of upwardly and rearwardly slopingwater tubes IE. A row of tubes IBeXtends forwardly from the drum ill toa steam drum l9 located above the water drum l5. These tubes l8 supportthe roof 2!) of the boiler. Beneath the tube bank Hi there is provided acombustion'chamber 22 having a front wall 23, a rear wall 2 and sidewalls 25. A wall 21 is provided in the rear of the tube bank l2,

' with a gas outlet 28 between the upper portion of this wall and thesteam-and-water drum ll].- Suitable balfies 29 are installed to directthe hot gases from the combustion chamber 22 into con tact successivelywith the tube banks l4, l6 and i2, and thence to the outlet 28 in awell-known manner.

A row of upright water wall tubes is associated with the rear wall 24 tosupport this wall and protect it from the heat of the combustion nectedto the lower front portion of the water drum H, beneath the tubes Hi,and in order to maintain adequate ligaments in the drum the ends of thetubes 3b may be staggered as shown in Figs. 3 and 4. The lower ends ofthe water wall tubes 30 are connected to a horizontal header3l to whichwater is supplied from the drum ll through a row of downcomer tubes 32located in the rear of the tubes 38.

It will now be apparent that with the construction as so far describedthere will be a rapid circulation of water from the drum Ill downwardlythrough the tubes 1 2, thence forwardly through the drum I l and thetubes M to the drum l5, and thence rearwardly through the tubes IE tothe drum ill. The steam which is generated in the tubes I4 and IE willbe carried along with the water and released in the drum IE3, whence itwill flow through the tubes It to the drum l9 and from this drum to aplace of use. Large quantities of steam will be generated in the waterwall tubes 38 and discharged upwardly into the drum H, and the rapidforward circulation of water through this drum may sweep this steam intothe water tubes I4 to mingle with the steam which is being generated inthese latter tubes. This may cause so much congestion in the tubes M asto chamber. The upper ends of these tubes are conprevent adequatecirculation therethrough, and the tubes may be seriously overheated.This is particularly true of the tubes in the lowermost row, which aresubjected to intense radiant heat.

In order to avoid this difiiculty I provide an improved baffling means34 in the interior of the drum I l to direct the steam away from thelower rows of tubes 14 and into tubes which are remote from the waterwall tubes in a direction circumferential of the drum. This steam ispreferably directed into certain of the tubes l2, thus causing thesetubes to serve as upcomers which conduct the steam upwardly to the upperdrum H]. For this purpose I mount within the drum II a plate 35 whichslopes upwardly and rearwardly above the upper ends of the water walltubes 30. The front or lower edge of this plate is located between thetubes 3!! and the lowermost of the tubes [4. For convenience ininstalling and removing this plate, its front edge portion may be boltedto a strip 36 which is welded to the interior of the drum wall. Thebottom surface of the plate 35 is provided with depending ribs 38 whichconverge in pairs in the rearward direction. Steam flows upwardly fromthe tubes 30 to the plate 35 and is thereby compelled to flowrearwardly, the ribs 38 serving to concentrate this steam into severalseparate streams. These streams are directed upwardly into certain ofthe tubes l2 which lead directly to the drum l0, and for this purpose Ipreferably utilize a series of conduits in the form of channel members39 which are spaced apart from each other in a direction longitudinal ofthe drum. These channel members are open toward the rear, and they slopeupwardly and rearwardly at a steep angle from the rear edge of the plate35. Their lower ends may be bolted to the plate, and their upper endsmay be bolted to a strip 40 which is welded to the interior of the drumwall between the tubes l2 and M. It will be noted from Fig. 4 that theupper end of each channel member 39 is located directly beneath one ofthe tubes I2, and that the lower end of each channel member is locatedbetween two of the converging ribs 38.

t will now be apparent that in the operation of the boiler there will bea rapid circulation of water downwardly from the lower drum H throughthe downcomer tubes 32 to the header 3! and thence upwardly through thewater wall tubes 39. These tubes fill will discharge large quantities ofsteam into the drum, and this steam will rise through the water until itencounters the plate 35 and thence will travel upwardly and rearwardlyalong the lower surface of the plate. During this rearward travel thesteam will be directed by the inclined ribs 38 into several concentratedstreams which are spaced apart in a direction longitudinal of the drum,and these streams will flow upwardly through the channels 38 into thetubes l2 thereabove which lead directly to the steam-and-water drum Hi.Because of the comparatively wide spacing between the channels 39 thereis ample area for the normal circulation of water forwardly through thedrum H to the lower ends of the water tubes M, and the bafileconstruction will prevent this water circulation from carrying any ofthe steam into these tubes. The baffles are simple and inexpensive tomanufacture and they allow ready access to the tubes for cleaningpurposes.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. A steam boiler comprising a horizontal water drum, downcomer watertubes connected at their lower ends to the drum, upcomer water tubesconnected at their lower ends to the drum, a row of water wall tubesconnected at their upper ends to the drum and arranged to dischargesteam into the drum, and bafile means spaced above the upper ends of thewater wall tubes and arranged to concentrate the steam discharged by thewater wall tubes into streams spaced apart longitudinally of the drumand to direct said streams into certain of the upcomer tubes, thedowncomer tubes serving to deliver water to the drum which flows betweenthe said concentrated streams of steam and thus to upcomer tubes on theother side of said streams.

2. A steam boiler comprising a horizontal water drum, downcomer watertubes connected at their lower ends to the drum, upcomer water tubesconnected at their lower ends to the drum, 2. row of water well tubesconnected at their upper ends to the drum and arranged to dischargesteam into the drum, baffle means spaced above the upper ends of thewater wall tubes and arranged to concent-rate the steam discharged bythe water wall. tubes into streams spaced apart longitudinally of thedrum, and spaced conduits to direct said streams upwardly into certainof the upcomer tubes, the downcomer tubes serving to deliver water tothe drum which flows between the said conduits and thus to upcomer tubeson the other side of said conduits.

3. A steam boiler comprising a horizontal water drum, downcomer watertubes connected at their lower ends to the drum, upcomer water tubesconnected at their lower ends to the drum, 2. row of water wall tubesconnected at their upper ends to the drum and arranged to dischargesteam into the drum, bafile means spaced above the upper ends of thewater wall tubes to deflect the steam discharged by the water wall tubesand including depending ribs which converge in pairs in the direction offlow to concentrate the steam into streams which are spaced apartlongitudinally of the drum, and spaced conduits to direct said streamsupwardly into certain of the upcomer tubes, the downcomer tubesservingto deliver water to the drum which flows between the said conduits andthus to upcomer tubes on the other side of said conduits.

4. A steam boiler comprising a horizontal water drum, a plurality ofrows of water tubes connected to the upper portion of the drum andextending upwardly therefrom, means to direct hot gases into contactwith the water tubes, a row of water wall tubes connected to the frontside of the drum below the water tubes and arranged to discharge steaminto the drum, bafile means spaced above the upper ends of the waterwall tubes to deflect the steam rearwardly and including depending ribswhich converge in pairs in the rearward direction to concentrate thesteam into streams which are spaced apart longitudinally of the drum,and upwardly extending conduits arranged to di ect said streams intocertain of the water tubes which are remote from the water wall tubes ina direction circumferential of the drum.

5. A steam boiler comprising a horizontal water drum, a plurality ofrows of water tubes connected to the upper portion of the drum andextending upwardly therefrom, means to direct hot gases into contactwith the water tubes, a row of water wall tubes connected to the frontside of the drum below the water tubes and arranged to discharge steaminto the drum, an upwardly and rearwardly sloping plate spaced above theupper ends of the water wall tubes to deflect the steam rearwardly, ribsdepending from the plate and converging in pairs in the rearwarddirection to concentrate-the steam into streams which are spaced apartlongitudinally of the drum, and

channel shaped members open toward the rear and sloping upwardly andrearwardly to direct said streams 'into certain of the Water tubes'whichare remote from the water Wall tubes in a direction circumferential ofthe drum.

GUSTAV A. REHIVI.

